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// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
import {  create_hash as createHash,  DenoHash,  digest_hash as digestHash,  update_hash as updateHash,} from "./wasm.js";
import * as hex from "../../encoding/hex.ts";import * as base64 from "../../encoding/base64.ts";import type { Hasher, Message, OutputFormat } from "../hasher.ts";
const TYPE_ERROR_MSG = "hash: `data` is invalid type";
export class Hash implements Hasher {  #hash: DenoHash;  #digested: boolean;
  constructor(algorithm: string) {    this.#hash = createHash(algorithm);    this.#digested = false;  }
  /**   * Update internal state   * @param data data to update   */  update(data: Message): this {    let msg: Uint8Array;
    if (typeof data === "string") {      msg = new TextEncoder().encode(data as string);    } else if (typeof data === "object") {      if (data instanceof ArrayBuffer || ArrayBuffer.isView(data)) {        msg = new Uint8Array(data);      } else {        throw new Error(TYPE_ERROR_MSG);      }    } else {      throw new Error(TYPE_ERROR_MSG);    }
    // Messages will be split into chunks of this size to avoid unneccessarily    // increasing the size of the WASM heap.    const CHUNK_SIZE = 65_536;
    for (let offset = 0; offset < msg.length; offset += CHUNK_SIZE) {      updateHash(        this.#hash,        new Uint8Array(          msg.buffer,          offset,          Math.min(CHUNK_SIZE, msg.length - offset),        ),      );    }
    return this;  }
  /** Returns final hash */  digest(): ArrayBuffer {    if (this.#digested) throw new Error("hash: already digested");
    this.#digested = true;    return digestHash(this.#hash);  }
  /**   * Returns hash as a string of given format   * @param format format of output string (hex or base64). Default is hex   */  toString(format: OutputFormat = "hex"): string {    const finalized = new Uint8Array(this.digest());
    switch (format) {      case "hex":        return new TextDecoder().decode(hex.encode(finalized));      case "base64":        return base64.encode(finalized);      default:        throw new Error("hash: invalid format");    }  }}